An Organic Light Emitting Diode (OLED) has the advantages of fast response, wide temperature range, self-illumination, flexible display, etc. It is known as the third generation display technology after cathode ray tube display and liquid crystal display. With the increasing market demand, the development and production of the flexible OLED has become a hot field in the display industry. However, since organic materials are particularly sensitive to external water and oxygen, flexible encapsulation technology is directly related to the display life of the OLED, and is also one of the bottlenecks restricting the development of the OLED.
At present, the flexible OLED encapsulation mainly adopts a thin-film encapsulation structure (TFE) in which an inorganic layer and an organic layer are alternately stacked, and it is required to not only fully shield the external water and oxygen, but also effectively cover particle contamination that cannot be avoided in the production process, and buffer stress generated during bending and folding. However, since the monomer used for coating the organic layer is better in fluidity and the boundary of the organic layer is not well controlled, a retaining wall is disposed on the periphery of the display region to block the flowing organic layer monomer. Because the material of the retaining wall is also an organic material, the water vapor is easy to penetrate. In order to completely block the overflow of the flowing organic monomer, at least two retaining walls are generally provided. This requires that the outermost boundary of the inorganic layer of the TFE package should extend to cover the outermost retaining wall, so as to ensure that the edge does not invade by the water and oxygen quickly, but this will cause the boundary of the TFE package structure to expand too much, which is not conducive to narrow frame design.